 DRLAs Question, Rich idle mixture? |
|
|
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
|
  |
| sdoolin |
 Jul 2 2023, 10:41 AM
Post
#1
|
|
Member  Group: Members Posts: 359 Joined: 1-May 14 From: LouKY Member No.: 17,299 Region Association: None  |
2056, dual Dellortos, has been running well for a few years, except in hot humid weather. When it gets hot out, she is hard to start once warm, gotta open throttles all the way. Leaving from a red light also difficult, gotta "clear" the carbs out by opening throttle. Runs fine in high RPM (throttles open(ish)).
Current set-up: Idle Jet = 55 Main Jet = 150 Emulsion Tube = 64 Air Correction (jet stack holder) = 180 Venturis = I forget, but she runs well in mild temps. I am thinking idle jets can go down a size to 50, or maybe 45? Pic because pics help everything (and don't bash my hex bar linkage, I quite like it)...  |
   |
 
|
| GregAmy |
Jul 2 2023, 10:50 AM
Post
#2
|
|
Advanced Member Group: Members Posts: 2,311 Joined: 22-February 13 From: Middletown CT Member No.: 15,565 Region Association: North East States 
|
You just never really know until you're running wideband...
I tend to run the 2056cc race car really lean on idle, as I want to avoid loading the plugs. Like, 14+ AFR if not higher. And it seems I'm always changing jets based on weather conditions. The street car is running Microsquirt...I am soooo tempted to do that on the race car. |
|
|
|
| r_towle |
Jul 3 2023, 07:54 AM
Post
#3
|
|
Custom Member Group: Members Posts: 24,585 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States
|
First, get rid of that hex bar linkage.. (IMG:style_emoticons/default/smile.gif)
Sounds like you may be flooding it. Hard to check but possibly tune the idle circuit only by downsizing the jet until you have a nice brown spark plug. I use a simple 02 sensor stuffed up the tailpipe hooked up to a gauge. You get a combined reading…better than nothing. Heat gun on each exhaust tube also helps. Valve adjustments need to match. Chris Foley has a great setup of exhaust gas temp sensors mounted in header stub pipes. This, imho, is the only way to be really accurate. It will also show you why hexbar linkage is bad (IMG:style_emoticons/default/smile.gif) |
|
|
|
| yeahmag |
Jul 3 2023, 10:53 AM
Post
#4
|
|
Advanced Member Group: Members Posts: 2,422 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California
|
From my experience:
1) You can't tune well without a wideband 02 2) I've never had a Dell that ran well with less than a 60 idle jet 3) Not sure what that emulsion tube is, it should be the ".2" https://vwparts.aircooled.net/Dellorto-DRLA...-2-p/9164.2.htm 4) Venturi greatly impacts the main jet sizing. You need to know this. 5) 180 is a good starting point on the air correction jet 6) What pump jets are you running? 7) How many turns out are your idle mixture screws? |
|
|
|
| GregAmy |
Jul 3 2023, 01:00 PM
Post
#5
|
|
Advanced Member Group: Members Posts: 2,311 Joined: 22-February 13 From: Middletown CT Member No.: 15,565 Region Association: North East States
|
|
|
|
|
| sdoolin |
Jul 4 2023, 08:00 AM
Post
#6
|
|
Member Group: Members Posts: 359 Joined: 1-May 14 From: LouKY Member No.: 17,299 Region Association: None |
Yep, I have a copy (actually two of them) of the Dellorto Superformance Tech Book. Been reading out of it since the late 80s.
Pump Jets = 35 Mixture screws all 2.5 - 3 turns out. Looking for a previous post to find my Venturi size. Y'all bashed my hexbar linkage... |
|
|
|
| 914Toy |
Jul 4 2023, 08:15 AM
Post
#7
|
|
Senior Member Group: Members Posts: 718 Joined: 12-November 17 From: Laguna beach Member No.: 21,596 Region Association: Southern California
|
Agree with the comments above.
On hot start difficulty, turn on ignition power and let the fuel pump run for 10 to 15 seconds - fills the float bowls - before you crank the engine. Then start cranking the engine while slowly pressing the accelerator. |
|
|
|
| MarkV |
Jul 5 2023, 12:01 AM
Post
#8
|
|
Fear the Jack Stands Group: Members Posts: 1,493 Joined: 15-January 03 From: Sunny Tucson, AZ Member No.: 154 Region Association: None |
2056 With Delortos & Hex Bar
Vents - 34 Idle - 60 Main - 132 Air - 180 No problem hot starting... you sure it isn't ignition / timing related? |
|
|
|
| rhodyguy |
Jul 5 2023, 10:41 AM
Post
#9
|
|
Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,084 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
What are you using for gaskets under the intakes?
|
|
|
|
| sdoolin |
Jul 5 2023, 01:12 PM
Post
#10
|
|
Member Group: Members Posts: 359 Joined: 1-May 14 From: LouKY Member No.: 17,299 Region Association: None |
My venturis are 34 mm (Jake Raby suggested).
Intake gaskets are OE replacement ("phenolic" spacers). Timing is 28 full advance |
|
|
|
| yeahmag |
Jul 5 2023, 04:07 PM
Post
#11
|
|
Advanced Member Group: Members Posts: 2,422 Joined: 18-April 05 From: Pasadena, CA Member No.: 3,946 Region Association: Southern California
|
What is the timing at idle?
|
|
|
|
| rfinegan |
Jul 5 2023, 04:56 PM
Post
#12
|
|
Senior Member Group: Members Posts: 973 Joined: 8-February 13 From: NC Member No.: 15,499 Region Association: MidAtlantic Region
|
QUOTE(yeahmag @ Jul 5 2023, 06:07 PM)  What is the timing at idle? shoot for about 10 +/- btdc and a total of 28 all in at 3k |
|
|
|
|
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:
|
Lo-Fi Version | Time is now: 2nd June 2024 - 10:57 AM |
Invision Power Board
v9.1.4 © 2024 IPS, Inc.